Embodiments of the present invention relate to the plasma etching of a substrate.
In the fabrication of electronic components and circuitry, a plasma of a process gas may be used to process semiconductor, dielectric and conductor materials, such as for example, silicon, silicon dioxide, and metal-containing layers, on a substrate. The substrate may be a semiconductor wafer or dielectric material. The substrate materials are typically formed by chemical vapor deposition (CVD), physical vapor deposition (PVD), oxidation or nitridation processes. In a typical CVD process, a plasma is provided in the chamber to deposit material on the substrate. In a typical PVD process, a target facing the substrate is sputtered to deposit target material on the substrate. The substrate is then etched by forming a patterned etch-resistant material, such as resist or hard mask, on the substrate, and etching exposed portions of the substrate by a plasma to form features such as gates, vias, contact holes and interconnect lines, in the substrate. The plasma may also be used in other substrate fabrication processes, such as post-etch treatments and in chamber cleaning processes.
However, conventional plasma processes often fail to provide good etch rate uniformity across the substrate. For example, in etching processes, the peripheral edge of the substrate may often be etched at faster etching rates than the central portion of the substrate. The non-uniform etching rates may arise from a non-uniform distribution of energized plasma species across the substrate, temperature variations, or other factors. It is difficult to control the etching process to obtain uniform etching rates across the surface of the entire substrate.
Thus it is desirable to be able to generate and control a plasma to etch a substrate with good etch rate uniformity across the substrate.
A substrate etching chamber comprises a substrate support to support a substrate in a process zone, a gas supply to introduce a process gas into the process zone, an inductor antenna to inductively couple energy to the process gas to form a plasma of the process gas in the process zone, a magnetic field generator to generate a magnetic field in the process zone, the magnetic field generator comprising first and second solenoids disposed about the process zone and a power supply to power the solenoids, a controller adapted to control the power supply of the magnetic field generator to pass a first current through the first solenoid and pass a second current through the second solenoid, the second current being in the opposite direction of the first current, and an exhaust to exhaust the process gas.
In another aspect, a substrate etching method comprises placing a substrate in a process zone, introducing a process gas into the process zone, inductively coupling energy to the process gas to form a plasma in the process zone, generating a magnetic field in the process zone by providing a first current to a first solenoid and a second current to a second solenoid, the first current being in the opposite direction to the second current, and exhausting the process gas from the process zone.
In yet another aspect, the substrate etching chamber comprises a substrate support to support a substrate in a process zone, a gas supply to introduce a process gas into the process zone, a gas energizer comprising an inductor antenna to inductively couple energy to the process gas to form a plasma of the process gas in the process zone and an RF power supply to pass an RF current through the inductor antenna, a magnetic field generator to generate a controllable magnetic field in the process zone, the magnetic field generator comprising first and second solenoids disposed about the process zone and a DC power supply to pass direct current through the first and second solenoids, and an exhaust to exhaust the process gas.
In yet another aspect, the substrate etching method comprises placing a substrate in a process zone, introducing a process gas into the process zone, inductively coupling energy to the process gas to form a plasma in the process zone by providing RF current to an inductor coil, generating a magnetic field in the process zone by providing direct current to first and second solenoids, and exhausting the process gas from the process zone.